) died just moments after watching members of the Apollo 11 crew walk on the moon. After hearing Neil Armstrong's famous "one small step for man" line, Cooper uttered what would be his last living word: a simple "Bravo." However, Bert got his final curtain call when Don (Jon Hamm) saw a vision of the shoeless, idiosyncratic figurehead dancing with secretaries and singing "The Best Things in Life Are Free," a nice tribute to the Tony-winning actor's musical theater background.But was Cooper's song-and-dance number actually a warning to Don, who had secured his own future by helping Roger (John Slattery) sell the company to competitor McCann-Erickson? TVGuide.com chatted with Mad Men creator Matthew Weiner about saying goodbye to Cooper, what it will mean for Don & Co., and the challenge of crafting a final season that is split up over two years. (Weiner, who directed the midseason finale, is in the process of writing the series finale.) Plus: Has Don finally passed the torch to Peggy (Elisabeth Moss)?When did you decide that Bert Cooper was going to die? And what was the motivation behind the musical send-off?Matthew Weiner: We started the season with the idea that he was going to pass away during the moon landing and that would throw Don's rise within his own company into jeopardy. Then I heard the song on old-time radio — this is the wonderful irony of satellite radio. I heard Frances Langford singing it. It just spoke to me. The song has a very simple message from the Great Depression. I felt right away that Bert's ghost would sing this to Don. I've been working with Bobby Morse for seven years, and he is a treasure. You can see his boyish charm when he's dancing. I'm not going to say how old the man is, but it's very impressive. We felt it was OK for Bert to break character in this moment in Don's mind.

What's Don feeling in that moment? Weiner: Don gets a chance to absorb the emotions of loss and what isimportant in the midst of the company moving on. [We wanted it] to be a bittersweet turn on the triumph of them selling their company. Because they did actually sell their company. Is that a triumph? Or is there something more important in life than that?

Certainly the "triumph" once again comes at the cost of Don's personal life. I loved how understated the breakup was between Don and Megan (Jessica Pare). Weiner: We were very conscious as we were breaking the season that this not be a television breakup. These people love each other, they're married, their relationship has changed obviously. From the moment she left advertising and decided to become an actor, Don has had trouble with her being separate. I love the idea that they're both fighting to keep it together in the most delusional way throughout the season. Don lied to her about losing his job because he didn't want to move out there and fight for his business. Megan had a threesome, striving to hold them together. But the fact is, when it comes time in a long-term relationship to make a permanent decision, she says, "What are we doing?" and he says, "I know." It was a very short scene that to me was harvesting the reality. These things are irreparable on some level, but hopefully the way that it moves was realistic. We all felt it was.

Roger really had his moment in this episode. Weiner: The story we wanted to tell in "Waterloo" is that this catastrophe was a motivation for people to rise. Roger having disappointed Cooper is a chance for him to try and be more and prove he has a vision. Whether it's good or bad, he definitely steps up.

And so did Peggy during her stellar Burger Chef pitch. Was there a bit of Don passing the torch in that moment?Weiner: I don't know. Pete says to Don in the pilot, "There's plenty of room at the top." The idea that Peggy could work alongside Don is interesting to me. Don and Peggy start the season as far away from each other as possible. It was about them reestablishing their connection ... and Don saying, "I'm not going to be selfish; I'm going to let you do this," was definitely an important part of the story. What I love about how we pulled this Peggy pitch off is [that] it is a true act of her conscience and personal life and confidence. Part of the story was that Don can't give that to her. She thought when she fired somebody that she was the boss, and it's so much more complicated than that. Seeing her make that story personal was exciting. It's a very risky pitch too. I know it becomes sentimental and emotional, but mentioning Vietnam in the middle of a business meeting in the middle of 1969 is a touchy maneuver. So, is he passing the torch? Or is she grabbing the torch and he's saying, "Good. That's all I wanted you to do"?

These last two episodes have reflected on Peggy's troubled history with motherhood, especially when she breaks down hugging Julio. Was it important to remind the audience of that history as we head into the home stretch?Weiner: Absolutely. Julio, as people may have observed, is about the age of the child she gave away. Her attachment to him is a revelation of something she's missing. A lot of her life is really good, but I think she has a psychic scar from that moment.

Despite the final two episodes' power, you now have to contend with the split season. Do you worry about losing the momentum you were building up?Weiner: Things like momentum and all the sports analogies don't really fit for what we're doing here. We're telling a story and we tell as much story as we have. What I really felt was the challenge of this split season was to make people feel like they got a whole season's worth of story. [We hoped] that in these seven episodes you would see an earned transformation and that there would be some satisfaction that the story isn't over, but the story has moved. That's really all we were trying to do. We're in the entertainment business, and that involves engaging the audience. If people are frustrated or dismissive of things ... it's not because we don't care, it's because we're telling the story the way we tell it. I really try to not leave things on the table.

Were you surprised by what frustrated fans this season?Weiner: I did hear people say, "Why is Joan [Christina Hendricks] so mad at Don? Why is Peggy so mad at Don?" Don ruined Peggy's relationship and pulled her away from her independence at another firm and then flamed out. Don cost Joan the equivalent of $7 million right now — I don't think they're going to be friends.

So, what can we expect from the final seven episodes?Weiner: The second half of the season is a continuation of what you saw. What's happened in the show is going to be taken into consideration as we move forward. We tell the story on a very human scale — there's no explosions or gunplay. The only ammunition we have is the mystery of what we're going to pay attention to. There are going to be stories in there that people probably think are frivolous that I've always wanted to tell. Stories like Betty and Bobby going on the field trip is something I've been talking about in the room since the first season. It's nice to find a place for something, but there's going to be a lot of stuff that never ends up in the show. We're dealing with that now. All I can tell you is everyone here has every intention of engaging the audience through the end of the show.

To follow Bert Cooper's Napoleon metaphor, is Don officially out of exile? Is his own personal Waterloo still to come?Weiner: We were telling the story of ... Don working his way up in his own company and getting control, on some level, of all of his worst behavior. Don behaves without alcoholic impulsiveness, with some integrity, because it was important to him. [He] succeeded, but what did he win? That's definitely part of the show as it goes on.

Mad Men's final episodes will air in 2015. In the meantime, watch previous episodes here. What did you think of the finale?